Two people have been killed due to a roof collapse after a blast in a household fireworks factory in Lahore.According to police, a blast occurred in the house of a man named Iqbal, when he along with his son, Tanvir and wife were busy making explosives used in fireworks, in the area of Harbanspura police station. The intensity of the blast made the roof of the house collapse. Rescue teams and police rushed to the scene but Iqbal and his son, Tanvir were found dead. Iqbal's wife and four other children were rescued by the rescue teams with the help of local residents and taken to the hospital.Two years ago, a similar blast occurred in another factory in this area, after which the local administration was also informed about the banned activities going on in the above mentioned house, but no action was taken.